Instead of cleaning it, as said before the soot aids the heat transfer, just make a bag and put it in if getting other things dirty in your pack. Any old cotton..denim is good.CG
I don't clean mine, don't see the point, especially the chimney.
If you do want to though, pink Brillo pads are the answer. Many a scout camp has been spent cleaning the outside of billies from soot when we forgot to "fairy up" the outside of them. We always used the pink Brillos and elbow grease.
I don't clean mine, don't see the point, especially the chimney.
From painful experinece you only forget to "fairy" up the bIllie once